The subject application discloses a means to drive a work element against a work object and additionally provides the capability of selectively engaging individual work elements from a plurality of available elements so that complex operations necessitating precise movement and timing functions may be carried out. The subject invention has utility in many fields with textile manufacturing processes being one of these fields. For example, yarn can be accurately metered and fed from the yarn source to a process station by utilizing the teachings of the subject invention with the work elements serving as plungers which positively engage the yarn and displace it as desired for the feeding and metering operation.
Additionally, the work element or driven member may be a yarn implanting needle, a severing means or any of a variety of driven members utilized in textile operations. It is to be noted that textile use is but one example and fields of use are actually quite limitless in view of the physical characteristics of the driving member, i.e., the band-like member. In particular, the lightweight of the band-like member and small area necessary for its containment make it adaptable to many complex systems.
For a more precise understanding of some of the uses of the subject invention, reference is hereby made to copending Application Ser. Nos. 699,904, 700,413 and 699,906.
In many types of machinery, tremendous forces are necessary to drive work elements such as for example, needles of a tufting machine. Conventionally, needles, in excess of a thousand in some systems, are driven by driving means usually comprising cam or eccentric shaft driven elements which are massive in size and weight. It becomes prohibitive to develop driving forces for individual needle units by conventional means since linkage and the driving means in general cannot be confined to a small enough space to make such machines feasible. However, many advantages are present when individual needle selection is enabled as for example, needles may be positioned in series formation so that different needles within each series are supplied with different colored yarns. Thus, for patterning or reproducing designs in colored yarns, one of the series of needles may be selected at a time to tuft a desired color. To develop such a system, however, the selection and driving means must be relatively small and lightweight so as to be confinable to a restrictive area. Conventional equipment, with its mass, is unsuitable.